The invention originates in the search for a solution to the problem of driving the compaction rollers of a compactor.
According to a first known embodiment, the compactor comprises a single compaction roller which is mounted to rotate with respect to the frame of the compactor with the interposition of supple vibration-damping elements. A hydraulic motor, generally with low speed of rotation and high torque, is coupled to the compaction roller and ensures drive thereof, being placed at one end of and coaxial to said compaction roller.
In order to improve the efficiency of compaction, an eccentric mass is placed in the hollow interior of the compaction roller, and is driven in rotation by means of another motor, generally constituted by a hydraulic motor with high speed and low torque. This other motor is placed at the other end of the compaction roller, coaxially thereto, and drives the eccentric mass via a shaft.
In order to improve the manoeuvrability of compactors, particularly in bends, certain compactors comprise two coaxial compaction rollers in line with each other and coupled to two distinct hydraulic motors. In this way, the rollers may have different rotations, which makes it possible to avoid the destruction of the compacted ground. On the side where the motor for driving the eccentric mass is already placed, it is not possible to couple the motor driving the corresponding compaction roller directly to this compaction roller. The known solution consists in moving said motor driving the compaction roller out of centre; in placing it where there is room, i.e. next to the motor for driving the eccentric mass; and in coupling the drive shaft of the motor driving the compaction roller to said compaction roller via a ring gear and gear pinions. The assembly is complex, cumbersome, heavy and expensive.
It is an object of the invention to overcome these drawbacks by proposing a solution where the two motors located on the same side of one of the compaction rollers are disposed coaxially to each other and to this compaction roller. To that end, it was necessary to study a novel hydraulic motor before applying it to compactors, such hydraulic motor being provided with a brake.